diff --git a/packages/opencode/src/cli/cmd/tui/app.tsx b/packages/opencode/src/cli/cmd/tui/app.tsx
index ab3d09689252..0ffa5a5a90b1 100644
--- a/packages/opencode/src/cli/cmd/tui/app.tsx
+++ b/packages/opencode/src/cli/cmd/tui/app.tsx
@@ -16,6 +16,7 @@ import { DialogModel, useConnected } from "@tui/component/dialog-model"
 import { DialogMcp } from "@tui/component/dialog-mcp"
 import { DialogStatus } from "@tui/component/dialog-status"
 import { DialogThemeList } from "@tui/component/dialog-theme-list"
+import { DialogExperimental } from "@tui/component/dialog-experimental"
 import { DialogHelp } from "./ui/dialog-help"
 import { CommandProvider, useCommandDialog } from "@tui/component/dialog-command"
 import { DialogAgent } from "@tui/component/dialog-agent"
@@ -519,6 +520,17 @@ function App() {
       },
       category: "System",
     },
+    {
+      title: "Enable experimental flag",
+      value: "opencode.experimental",
+      slash: {
+        name: "experimental",
+      },
+      onSelect: () => {
+        dialog.replace(() => <DialogExperimental />)
+      },
+      category: "System",
+    },
     {
       title: "Switch theme",
       value: "theme.switch",
diff --git a/packages/opencode/src/cli/cmd/tui/component/dialog-experimental.tsx b/packages/opencode/src/cli/cmd/tui/component/dialog-experimental.tsx
new file mode 100644
index 000000000000..91d2fb18fd09
--- /dev/null
+++ b/packages/opencode/src/cli/cmd/tui/component/dialog-experimental.tsx
@@ -0,0 +1,135 @@
+import path from "path"
+import { createMemo, createResource } from "solid-js"
+import { DialogSelect } from "../ui/dialog-select"
+import { useSync } from "../context/sync"
+import { useDialog } from "../ui/dialog"
+import { DialogPrompt } from "../ui/dialog-prompt"
+import { useToast } from "../ui/toast"
+import { Flag } from "@/flag/flag"
+
+function esc(value: string) {
+  return value.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")
+}
+
+function parse(text: string) {
+  return text.split(/\r?\n/).reduce(
+    (result, line) => {
+      const trimmed = line.trim()
+      if (!trimmed || trimmed.startsWith("#")) return result
+      const clean = trimmed.startsWith("export ") ? trimmed.slice(7).trim() : trimmed
+      const index = clean.indexOf("=")
+      if (index <= 0) return result
+      result[clean.slice(0, index).trim()] = clean.slice(index + 1).trim()
+      return result
+    },
+    {} as Record<string, string>,
+  )
+}
+
+function edit(text: string, key: string, value: string) {
+  const line = `${key}=${value}`
+  const lines = text.split(/\r?\n/)
+  const index = lines.findIndex((item) => new RegExp(`^\\s*(?:export\\s+)?${esc(key)}\\s*=`).test(item))
+  if (index !== -1) {
+    lines[index] = line
+    return lines.join("\n")
+  }
+  if (text.length === 0) return line + "\n"
+  const suffix = text.endsWith("\n") ? "" : "\n"
+  return text + suffix + line + "\n"
+}
+
+function label(key: string) {
+  return key.replace(/^OPENCODE_/, "").toLowerCase().replaceAll("_", " ")
+}
+
+export function DialogExperimental() {
+  const sync = useSync()
+  const dialog = useDialog()
+  const toast = useToast()
+
+  const file = createMemo(() => path.join(sync.data.path.directory || process.cwd(), ".env"))
+  const [text, { refetch }] = createResource(
+    file,
+    (target) => {
+      return Bun.file(target).text().catch(() => "")
+    },
+    { initialValue: "" },
+  )
+  const vars = createMemo(() => parse(text() ?? ""))
+  const flags = createMemo(() => {
+    const entries = Object.entries(Flag.types)
+      .filter(([key]) => key.includes("EXPERIMENTAL"))
+      .map(([key, type]) => ({ key, type }))
+    const set = new Set(entries.map((item) => item.key))
+    const extras = Object.keys(Flag)
+      .filter((key) => key.includes("EXPERIMENTAL") && !set.has(key))
+      .map((key) => ({ key, type: "boolean" as const }))
+    return [...entries, ...extras].toSorted((a, b) => a.key.localeCompare(b.key))
+  })
+
+  const options = createMemo(() =>
+    flags().map((flag) => {
+      const current = vars()[flag.key]
+      return {
+        title: flag.key,
+        value: flag.key,
+        description: label(flag.key),
+        category: flag.type === "number" ? "Numeric" : "Boolean",
+        footer: current ? `Current: ${current}` : undefined,
+      }
+    }),
+  )
+
+  return (
+    <DialogSelect
+      title="Experimental flags"
+      options={options()}
+      onSelect={async (opt) => {
+        const flag = flags().find((item) => item.key === opt.value)
+        if (!flag) return
+
+        let value = "true"
+        if (flag.type === "number") {
+          let input = vars()[flag.key]
+          while (true) {
+            const result = await DialogPrompt.show(dialog, flag.key, {
+              value: input,
+              placeholder: "Positive integer",
+            })
+            if (result === null) return
+            value = result.trim()
+            if (/^[1-9]\d*$/.test(value)) break
+            toast.show({
+              variant: "error",
+              message: "Value must be a positive integer",
+            })
+            input = result
+          }
+        }
+
+        const output = edit(text() ?? "", flag.key, value)
+        const saved = await Bun.write(file(), output)
+          .then(() => true)
+          .catch(() => false)
+
+        if (!saved) {
+          toast.show({
+            variant: "error",
+            message: `Failed to write ${file()}`,
+          })
+          return
+        }
+
+        process.env[flag.key] = value
+        await refetch()
+        dialog.clear()
+        toast.show({
+          variant: "success",
+          message: `Enabled ${flag.key} in ${file()}. Restart OpenCode to apply.`,
+          duration: 6000,
+        })
+      }}
+    />
+  )
+}
diff --git a/packages/opencode/src/flag/flag.ts b/packages/opencode/src/flag/flag.ts
index 0049d716d095..4b7358a566bb 100644
--- a/packages/opencode/src/flag/flag.ts
+++ b/packages/opencode/src/flag/flag.ts
@@ -1,9 +1,22 @@
+const meta: Record<string, "boolean" | "number"> = {}
+
 function truthy(key: string) {
+  meta[key] = "boolean"
   const value = process.env[key]?.toLowerCase()
   return value === "true" || value === "1"
 }
 
+function number(key: string) {
+  meta[key] = "number"
+  const value = process.env[key]
+  if (!value) return undefined
+  const parsed = Number(value)
+  return Number.isInteger(parsed) && parsed > 0 ? parsed : undefined
+}
+
 export namespace Flag {
+  export const types = meta as Readonly<Record<string, "boolean" | "number">>
+
   export const OPENCODE_AUTO_SHARE = truthy("OPENCODE_AUTO_SHARE")
   export const OPENCODE_GIT_BASH_PATH = process.env["OPENCODE_GIT_BASH_PATH"]
   export const OPENCODE_CONFIG = process.env["OPENCODE_CONFIG"]
@@ -54,13 +67,6 @@ export namespace Flag {
   export const OPENCODE_EXPERIMENTAL_MARKDOWN = truthy("OPENCODE_EXPERIMENTAL_MARKDOWN")
   export const OPENCODE_MODELS_URL = process.env["OPENCODE_MODELS_URL"]
   export const OPENCODE_MODELS_PATH = process.env["OPENCODE_MODELS_PATH"]
-
-  function number(key: string) {
-    const value = process.env[key]
-    if (!value) return undefined
-    const parsed = Number(value)
-    return Number.isInteger(parsed) && parsed > 0 ? parsed : undefined
-  }
 }
 
 // Dynamic getter for OPENCODE_DISABLE_PROJECT_CONFIG
diff --git a/packages/web/src/content/docs/tui.mdx b/packages/web/src/content/docs/tui.mdx
index 085eb6169f83..50785ebeed07 100644
--- a/packages/web/src/content/docs/tui.mdx
+++ b/packages/web/src/content/docs/tui.mdx
@@ -115,6 +115,20 @@ Open external editor for composing messages. Uses the editor set in your `EDITOR
 
 ---
 
+### experimental
+
+Quickly enable experimental OpenCode flags. This opens a picker and writes the selected flag to `.env` in your current directory.
+
+```bash frame="none"
+/experimental
+```
+
+:::note
+Restart OpenCode after changing an experimental flag.
+:::
+
+---
+
 ### exit
 
 Exit OpenCode. _Aliases_: `/quit`, `/q`